Fix Chroma type hint for Spaces runtime

app.py

@@ -1,5 +1,5 @@
 import os
-from typing import List, Tuple
+from typing import Any, List, Tuple
 
 import chromadb
 from chromadb.config import Settings
@@ -47,7 +47,7 @@ def build_chunks(articles: List[str]) -> Tuple[List[str], List[str]]:
     return ids, texts
 
 
-def ensure_collection() -> Tuple[chromadb.api.types.Collection, SentenceTransformer]:
+def ensure_collection() -> Tuple[Any, SentenceTransformer]:
     """Get or build the Chroma collection, persisting to disk."""
     client = chromadb.PersistentClient(path=CHROMA_DIR, settings=Settings(anonymized_telemetry=False))
     collection = client.get_or_create_collection(name=COLLECTION_NAME)